I don't think any serious person is suggesting we repeal the second amendment outright. I think there are some sensible measures that can be taken though. When Austrialia had a similiar incident happen in their country about 15 years ago, they didn't outlaw guns; but they did pass some laws outlawing some weapons and created more stringent rules for obtaining a gun. Since then, gun violence in Austrialia has plummeted.
https://www.washingtonpost.com/blogs/wonkblog/wp/2012/08/02/did-gun-control-work-in-australia/
As for arming everyone or putting guns in class rooms, that's a ****ing joke.
The last thing I want is to be surrounded by a bunch of yahoo George Zimmerman wannabes every time I go out of my house.
And as far as putting them in class rooms I would bet a nickel against everthing I own that some psycho teacher will go nuts and use it on a student way before it is used to stop an event like this from happening again.